A positioning method using height-constraint-based extended Kalman filter, suitable for a GNSS navigation and positioning system, comprises: obtaining an estimated state value of a current epoch by using an extended Kalman filter algorithm and according to an estimated state value of a previous epoch; constraining a positioning height of the current epoch by establishing a height constraint condition, so as to obtain an optimum estimated value of the current epoch and a corresponding mean square error, wherein the optimum estimated value satisfies the height constraint condition; further correcting the estimated state value by using a pseudorange obtained from the mean square error and a measured Doppler shift residual to obtain a final estimated state value of the current epoch, thus more accurately obtaining positioning information of a target to be positioned in the current epoch and enhancing the accuracy of GNSS navigation and positioning.