Intrinsic metal halide perovskite single crystal has attracted intensive attention in recent years due to its excellent optoelectronic properties. Also, controlled doping of metal halide perovskite with metal ions is a feasible way to adjust its optoelectronic properties. However, only a few metal ions (Bi3+, Fe3+, Sn2+) doping of lead halide perovskite single crystal works were reported. Here, we employed a low-temperature high-molarity crystallization (LTHMC) method to synthesize high-quality monovalent Ag ions doped CH3NH3PbBr3 single crystals. Ag+incorporation leads a 160 meV reduction on the bandgap of Ag-doped single crystals, while significant PL quenching was observed. P type behaviour of Ag-doped CH3NH3PbBr3 single crystals and enhancement on conductivity and carrier concentration were confirmed by Hall effect measurement. Space-charge limited current methods was adopted to obtain the mobility of various doping levels samples. Compared with pristine single crystal, the mobility of Ag-doped single crystal exhibits a near sixfold enhancement. Moreover, photodetector based on Ag-doped single crystal was fabricated, exhibiting better performance than undoped counterpart. This project manifests the successful introduction of silver ions in perovskite crystals while retaining the host lattice structure, presenting an effective path for adjusting the optoelectronic properties of perovskites.