In order to eliminate the impact of eccentric error and characters of tire surface in tire roundness error detection, an embedded system for measuring tire roundness error based on laser triangulation is designed. The error separation technique of modified reverse method is used to eliminate the eccentric error. According to the characters of rubber burr and depression stripe on tire surface, the filtering and fitting algorithm is designed to eliminate adverse effects.The least-square method is used to evaluate the roundness error of tire. Experimental results show that for large and small decorative pattern surface of the radial tire, the system can eliminate the impact of eccentric error and characters of tire surface effectively and complete the tire roundness error detection.