Intracavity phase locking of two beams emitting from a block of Nd:YAG medium side-pumped by laser diode array (LDA) was investigated experimentally. The interference fringes of the two beams occured at the output mirror. The coherent output power of 1.13 W was obtained with combination efficiency of 64.9% and coherence degree of about 60%. Only a metallic wire as a filter located at a suitable position close to the output mirror can efficiently lock the entire structure with less than 8% power loss.