This paper presents the improved burn-in method for the reliability of SRAM in Multi Chip Package (MCP). Semiconductor reliability is commonly improved by the burn-in process. Reliability Problem is very significant in the MCP which includes over two chips in a package because the failure of one SRAM chip has a large influence on the yield and quality of the other chips such as Flash Memory, DRAM, etc. Therefore the quality of SRAM must be guaranteed. To improve the qualify of SRAM, we applied the improved wafer level burn-in process using multi cell selection method in addition to the previously used methods and it is found to be effective in detecting particular failures. Finally, with the composition of some kinds of methods, we achieved the high quality of SRAM in MCP.