A kind of density wavelength-division multiplexing (DWDM) filter and PIN-TIA integrated optoelectrical device for upstream channels detection in wavelength-division multiplexing passive optical networks (WDM-PON) system is proposed. In order to achieve a parallel reflection beam for an efficient coupling and collimation to PIN-TIA, a novel structure design of a double single mode fiber core and self-focus lens is presented. Based on this device, a 32 channels array optical receiver module which can realize the demux and receiver performance in WDM-PON system is achieved. Through experiment, the responding bandwidth is from 100 Mbit/s to 1.25 Gbit/s, and the channel loss is from 0.3 dB to 6 dB.