A wireless laser communication system with multiple transmitter and auto-tracking is reported in this paper. The overall design, key optical and mechanical components, and servo-control sub-system are described including three laser transmitters at 800 nm, a beacon laser at 980 nm, optical detector, position sensitive detector, step motor and micro processor for auto-tracking. In experiments over a span distance of 1.3 km, percentages of error-free-second were measured to be more than 98% for 155 Mb/s during 24 hour continuous operation, and 95% for 622 Mb/s in a period of 8 hours, and bit error rate of less than 10-9. It is shown that the scheme of multiple transmitter and auto-tracking will improve the reliability of wireless laser communication systems.