The invention relates to a portable water quality sampler, which mainly comprises a water quality sampling probe, a telescopic pole, a sampling pipeline automatic winding and unwinding reel and a handheld terminal. The water quality sampling probe comprises a deep detection sensor and a sampling pump; the telescopic pole comprises a plurality of telescopic rods, a pulley block, a hook and a suspension seat; the sampling pipeline automatic winding and unwinding reel comprises a reeling disk, a winding motor, a counterweight, a cable, a sample conveying tube, a suspension balance frame and a reel bracket, and the handheld terminal comprises a LCD screen and keys. The whole system has the advantages of light quality, disassemble components and convenient carrying; the telescopic pole structure can be used to collect intermediate water samples in rivers, ditches and reservoir banks, the winding motor controls the reeling disk to adjust the putting-in depth of the probe for water quality sampling of different water depths, the deep detection sensor can be used for real-time detecting of the water depth of the probe so as to ensure the sampling pump can accurately acquire a surface layer, middle layer and bottom layer water sample, and the handheld terminal can be used for sampling horizon setting and sampling motor control.