The performance of a calorimeter prototype of PbWO 4 crystals has been tested by using 0.2-1.0 GeV electrons. The calorimeter comprises nine crystals, each 20 mm×20 mm×200 mm, arranged in a 3×3 matrix. A phototube was connected to each crystal to collect the signal. The energy resolution is obtained to be (σ/E) 2=((0.014±0.001)/E) 2+((0.025±0.001)/ E) 2+(0.000±0.027) 2 at 13°C, where E is the energy given in GeV. The position of the incident electron beam has been measured every 2 mm step. The position resolution at the center of the crystal is obtained to be ((2.6±0.1)/ E) 2+(0.4±0.6) 2 mm.