The Kuroshio intrudes westward and modulates the water masses in the South China Sea and continental shelf of East China Sea. There are two hot spots of Kuroshio intrusion; one is in the Luzon Strait and the other is in the waters off northeast Taiwan. It is noted that Kuroshio intrusion occurred synchronously when the upstream Kuroshio weakens during winter. This study attempts to identify the variability of the Kuroshio intrusion northeast of Taiwan associated with climate factors. The sea surface temperature (SST) front gradient magnitudes, used as the Kuroshio intrusion index, revealed that Kuroshio intrusion in northeast of Taiwan was gradually decreased, which was corresponding to the change of Kuroshio current velocity.