Abstract: To effectively solve the interlayer interference in comingled producing wells during development of multi-layer system and to maximize the production capacity of each layer, we have developed a double-layer separate producing technology is developed with gas-proof selective producing pump, which works very effectively on site, but it cannot separately produce more than 3 layers. Based on double-layer separate producing principle, we presented a concept of three-layer separate producing technology ’the producing pay overflowing one-way into tubing, interlayer produced liquid in the tubing overflowing in the form of bridge multi-stage, isolating the layers with packers and lifting by ordinary pumping unit’. By improving the check valve structure, a bridge-type separate-zone producing device is develope with a structure of ’two-way bridge flow channel, and valve ball centralizer one-way flow channel’, and designed three-layer separately producing technological string of ’bridge-type separate-zone producing device+Y211 packer+Y111 packer+ordinary tubing pump’. In 2013, the technology was used in two wells in Changqing Oilfield for the first time and worked very well, providing a new technical manner for multi-layer selective producing in wells in multi-layer development zones of Changqing Oilfield.