A high linearity up-conversion mixer is disclosed, which includes a voltage-to-current conversion circuit and an up-conversion mixer core circuit, the voltage-to-current conversion circuit has a differential signal positive input end for receiving an I/Q-channel positive baseband voltage signal and a differential signal negative input end for receiving an I/Q-channel negative baseband voltage signal, wherein the received positive and negative baseband voltage signals are low pass filtered by the voltage-to-current conversion circuit and are respectively converted to a first and a second current signal; the first and the second current signals are inputted to the up-conversion mixer core circuit to mix with local oscillator signals so as to output high linearity frequency-mixed signals. By embedding low-pass filters into the voltage-to-current conversion circuit of the up-conversion mixer, the present invention can ensure the high linearity of the up-conversion mixer while reduce the chip area and the current.