Abstract: Values of relative molecular mass (Mr) and distribution of Mr of β-glucan were determined and calculated by using 3 chromatographs of different types with their respective GPC softwares. The chromatographic conditions used were as follows: ① SB-804HQ gel chromatographic column (7.8 mm×300 mm); ② mobile phase: 0.2 g·L-1 sodium azide solution, with flow-rate of 0.5 mL·min-1; ③ column temp.: 35 ℃; ④ vol. of sample introduced: 25 μL; ⑤ detection: 2410 differential refraction detector; ⑥ the glucan standard series of Shodex Standard P-82 with known Mr were chosen as calibration standards. It was found that the average Mr of β-glucan of Grifola frondosa (GF-932) mycelia were in the range 134 195-251 053 amu, and the breadth parameters (Mr/Mn) of Mr distribution were in the range of 1.64-2.61. It was shown that the analytes were polymeric substances of high-purity with definite range of distribution of Mr.