Open the "Maven Projects" tab/window and clicking the "Reimport All Maven Projects" in the upper left corner starts to reload all dependencies from their repositories. The status bar informs about the process.

What lets you think that this is not working correctly? Maybe any of the dependencies can't be load from the repository?

just edit Pom.xml eg:type a space ，idea will pop up you should reimport maven。

Fix before IntelliJ 14

File [menu] -> Settings -> maven -> importing and uncheck "use maven3 to import project"

ref: http://youtrack.jetbrains.com/issue/IDEA-98425 (which may have a few other ideas too)

Fix IntelliJ 15+

Ran into this again, with IntelliJ 15 this time, which has no "use maven3 to import" option available anymore. The cause was that sometimes IntelliJ "doesn't parse maven dependencies right" and if it can't parse one of them right, it gives up on all of them, apparently. You can tell if this is the case by opening the maven projects tool window (View menu -> Tool Windows -> Maven Projects). Then expand one of your maven projects and its dependencies. If the dependencies are all underlined in red, "Houston, we have a problem".

You can actually see the real failure by mousing over the project name itself.

In my instance it said "Problems: No versions available for XXX" or "Failed to read descriptor for artifact org.xy.z" ref: https://youtrack.jetbrains.com/issue/IDEA-128846 and https://youtrack.jetbrains.com/issue/IDEA-152555

It seems in this case I was dealing with a jar that didn't have an associated pom file (in our maven nexus repo, and also my local repository). If this is also your problem, "urrent work around: if you do not actually need to use classes from that jar in your own code (for instance a transitive maven dependency only), you can actually get away with commenting it out from the pom (temporarily), maven project reload, and then uncomment it. Somehow after that point IntelliJ "remembers" its old working dependencies. Adding a maven transitive exclude temporarily might also do it, if you're running into it from transitive chain of dependencies."

Another thing that might help is to use a "newer version" of maven than the bundled 3.0.5. In order to set it up to use this as the default, close all your intellij windows, then open preferences -> build, execution and deployment -> build tools -> maven, and change the maven home directory, it should say "For default project" at the top when you adjust this, though you can adjust it for a particular project as well, as long as you "re import" after adjusting it.

Clear Caches

Deleting your intellij cache folders (windows: HOMEPATH/.{IntellijIdea,IdeaC}XXX linux ~/.IdeaIC15) and/or uninstalling and reinstalling IntelliJ itself. This can also be done by going to File [menu] -> Invalidate Caches / Restart.... Click invalidate and restart. This will reindex your whole project and solve many hard-to-trace issues with IntelliJ.

You don't have to reimport manually each time. You can enable auto-import as documented here. Change this in Settings -> Maven -> Import Maven projects automatically.

Maven Projects panel

Maven Projects tool window > Icon with green arrow and a box > Download Documentation:

See IntelliJ IDEA documentation for Version 14.1 or current version.

In IntelliJ 2018.2.3 Ultimate Edition, click on "Maven Projects" on the right hand side of the window (vertical text alignment). Then click the third button on the left in the toolbar (arrow pointing down to a horizontal line- not green for me).