The invention relates to a weak target detection tracking method based on a mixed coordinate pseudo-spectrum technology. The method comprises the steps of obtaining radar echo data; setting the widthand the number of speed filters; converting the resolution unit in the polar coordinate system into a Cartesian coordinate system to obtain a predicted Cartesian position of the resolution unit in thelast frame, and converting the predicted Cartesian position of the resolution unit into the polar coordinate system to obtain a predicted position of the resolution unit in the polar coordinate system; for each speed filter, constructing a pseudo spectrum according to the prediction position, and accumulating the intensity of each frame of pseudo spectrum to obtain a space domain accumulation plane and a speed domain plane of the speed filter; according to a preset detection threshold, judging whether a peak value accumulated by a speed filter is greater than the detection threshold, obtaining a spatial waveform and a speed dimension waveform after target multi-frame accumulation, and estimating a polar coordinate position and a Cartesian speed of the target; carrying out track backtracking; and outputting results. The method solves the problem that a traditional pre-detection tracking method cannot well process radar polar coordinate system data.