the MR command seems only support less than 4 bytes of length.
Is there a Ollydbg command like BPR in Softice? Or i misused MR command?

have you tried using view --->memory --->set break point on access
set memory break point on access or set memory breakpoint on write
olly stops when the code or resource or what ever is accessed or written to

or you can use run trace set condition

ctrl+t and specify it to pause in a range

you can combine and club other conditions also

like when eip > 401020 && eip < 401030 eax== 345678
and command is one of mov r32,imm mov r16,word ptr ds:[***]
etc

hope this helps

thanks a lot, it works nicely when i "set break point on access" on a heap range.