A packaging architecture is developed for MEMS tunable laser (MEMS-TL). The hybrid integration of chips is realized under high accuracy thermal control and precise alignment. The thermal conductivity of the laser chip has been improved up to 60% by the proper substrate design of device and epi-down bonding method. Under the analysis of heat flux, we employ a thermo-electric cooler (TEC) to stabilize the temperature. The substrate is designed to accommodate gain chips with minimal active optical alignment, thus reducing the packaging cost. With this packaging scheme, the insertion loss is greatly induced less than 1 dB due to the advantages of horizontal and vertical alignment in optical fiber fastening and laser diode bonding.