Hi Zhang Jing ,
I meet the same problem with you. Do you have solved the problem?
I use matlab 2016B x 64bit in Win10 professional x 64bit. I have install mbdtbx_MPC574xP, but there is no MBDT block while opening simulink library. It doesnot work even if I try to press F5.
I hava run the following step referencing to Setting the Path for Model Based Design Toolbox.
That's really strange. I've using the same setup without any issue. It's true that i do not have so many toolboxes but i think that could be a Matlab issue.
Here is what i've found out on Mathworks website: Simulink Library Browser doesn´t show any blocks - MATLAB Answers - MATLAB Central
Perhaps some of those answers will help you make it work.
Hope this helps!