Abstract: In order to fulfill the need of high-resolution, low-cost and miniaturized detector for current gamma camera, a silicon photomultiplier tube (SiPM) coupled with GAGG: Ce crystal array was adopted to form a new type of gamma camera detector instead of the conventional position-sensitive photomultiplier tube (PSPMT) coupled with crystal array. A symmetric charge division circuit (SCDC) and impedance bridge circuit were designed as a detector readout circuit, and the leading edge timing circuit was designed as a data acquisition trigger circuit. The experimental results show that the peak-to-valley ratio of the flood histogram reaches 3.84 under 511 keV ray excitation, and the mean energy resolutions are 10.63% and 9.71% respectively under 511 keV and 662 keV ray excitation when the detector voltage is 28.5 V at 25 ℃. It indicates that the detector has better resolution performance.