[en] A high resolution phoswich detector has been developed to reduce event mispositioning and improve the spatial resolution of the detector. Crystal identification electronics and algorithm is designed for identifying LYSO and YSO crystals in phoswich detector coupled to PMT. After shaping and filtering, events are sampled at 105 MSPS by an analog to digital converter (ADC) and acquired by FPGA. A crystal identification algorithm based on Auto-Regressive Moving-Average with noise (ARMAX) model is proposed. Excellent discrimination are (>98%) has been achieved without considering crosstalk between crystals. For LYSO/YSO array, the system achieves a discrimination rate of (93.6%). Then the 2D map of each kind of crystal has also been generated individually which has little overlap. (authors)