A water lubrication air compression system (100) disposes a lubricant heat dissipation system at a bearing chamber (13) close to the high pressure end of the compressor (1) for cooling and circulating lubricant due to the rise of temperature during operation of the compressor (1), hence enhancing the ability and stability of the compressor (1). On the other hand, a negative pressure system (5) is connected to the air chambers (17, 18) between the oil lubrication and the water lubrication of the compressor (1) in order to provide a negative pressure. If any leak of water vapor at the compressor chamber or oil vapor at the bearing chambers (12, 13), the negative pressure system (5) is able to produce a negative pressured condition toward the sealing structure so that the oil lubrication can be effectively isolated from the water lubrication and inter-contamination between the lubricant and water can be avoided.