The present paper discussed wood grading according to modulus of rupture (MOR) by near infrared (NIR) spectroscopy.The calibration model was built between MOR of wood and NIR data in the range of 1 000～1 400 nm with partial least square regression (PLS).The correlation coefficient (r) was 0.89 and the standard error of calibration (SEC) was 6.30 MPa.The MOR of 35 unknown samples was predicted using the model.Wood samples were graded according to their predicted values and true values.The rate of right prediction for A, B and C was 75.0%, 91.3% and 80.0% respectively, and the whole rate of right prediction was 88.6%.The result has proved that near infrared spectroscopy is a fast method for the determination of wood grade in the small clear samples.