and this
and the screen is dead when these occur.
It’s a memory corruption in some form. Probably you are writing out of bounds in an array.
IS the code snippet to reproduce the issue?
I don’t konw why ,is the LVGL memory not enough to cause this problem?
LVGL’s memory manager should be very stable, we have use it a lot even in extreme stress cases and it never failed so far.
It can be an out of memory issue too. Please increase LV_MEM_SIZE and enable all LV_USE_ASSERT_...s.
I have tried to increase LV_MEM_SIZE,but it 's not valid. then what 's LV_USE_ASSERT_…, they’re these?
after enabling all LV_USE_ASSERT_... s, what can i see?
Yes.
How do you mean not valid?
LVGL should stop in a while(1) loop if an internal error ocurres.
You should also enable logging to make it easier finding issues.
After enabling all LV_USE_ASSERT_... s, the screen change very slowly,i really can’t tolerate it. Colud you tell me what the reasons are probably?
Although i increase LV_MEM_SIZE,the the error is still existing,when it occurs the screen is still dead. 
I stll receive this error after i enable LV_USE_ASSERT_MEM_INTEGRITY…i also don’t receive other warmings about this error.
Maybe better is locate your code , what produce problem instead assert labs…
If the asserts didn’t help, then without a code example I can’t really tell more.
As @Marian_M suggested try to comment out parts of your code to find when it starts to work.