To meet the needs of high count rate and high time resolution in future high energy physics experiments, a prototype of gas photodetector with RPC structure was developed. Garfield++ simulated the detector's performance, and the single photoelectron performance of different mixed gases was tested with an ultraviolet laser. The detector uses a low resistivity () float glass so that it's rate capability is significantly higher than that of ordinary float glass(), the laser test results show that in MRPC gas(), the single photoelectron time resolution is best to reach 20.3 ps at a gas gain of . Increasing the proportion of  can effectively reduce the probability of photon feedback while hardly changing the time resolution and maximum gain. In addition to being applied to high-precision time measurement scenarios(eg:T0, TOF), the detector can also quantitatively test the single photoelectron performance of different gases and will be used to find eco-friendly MRPC gases.
 

gas photodetector, timing RPC, high time resolution, high-rate capability