This paper introduces a Ka-band 4-channel dual-stream phased-array joint radar-communication transceiver for the future radar-communication integrated wireless system. In order to enhance the signal to noise and distortion ratio in low input signal region and reduce the chip area, a current-flopping bi-directional active mixer is proposed. A variable-transmission-line-based phase shifter with tilting structure is introduced to achieve wide-band phase shifting and mitigate the in-band loss fluctuation. The proposed transceiver is designed and implemented in a 65nm CMOS technology. The chip area is 16.2 mm 2 . The measured TX peak saturated output power is 19.9 dBm and the output 1 dB compression point is 17.4 dBm. The measured RX minimum noise figure is 4.8 dB. System measurement results indicates that the proposed transceiver supports real-time centimeter-level 2D imaging and 400-Msym/s 64-QAM over-the-air (OTA) wireless link.