In order to satisfy the application requirements of high-speed free-space coherent optical communication, the high stability four-lane integrated laser module with different frequency in the same spectrum was fabricated. The method of the gradient feedback control was proposed and it distinguish control cases with five levels which were set by the feedback values of temperature. The current and temperature of each lane are controlled step by step based on the priority order in this method and that will reduce the temperature drift, the current jitter and the influence of servo system on the linewidth of lasers. This method was applied to the module and it needed the more accurate feedback values of the temperature. Hence, the passive feedback amplifying circuit of the temperature was adopted and it can eliminate the deviation caused by the current component. The temperature drift and the current jitter which were less than 0.001 ℃ and 0.6 μA, respectively, were tested. After being integrated into the module, the Lorentzian linewidth of four external cavity diode lasers were 4.5-7.5 kHz and the Allan variances were all less than 4×10－9. In the Free-Space Optical (FSO) communication, the bit error rates of four modulation formats were tested with four lasers in the module and the ultra-high speed free-space coherent optical communication with 4×50 Gb/s 16QAM was demonstrated. The experimental results show that the four-lane integrated module has a wide application prospect in the FSO communication.