Abstract：Aiming at the problem of low accuracy and divergence of positioning algorithm for ultra-wideband (UWB) sensors in time-different-of-arrival (TDOA) positioning mode, we propose a simple iterative least squares algorithm. This method has the advantages of a simple formula, convergent coordinates and high positioning accuracy. The main idea is to transform the TDOA localization equation into a nonstandard least squares form by the Pythagorean theorem. Then, the equation constraint relation between unknown variables is combined to transform the form with two unknown variables into a form with only one unknown variable. Finally, the convergence coordinate of UWB tag is calculated by iteration. Monte Carlo simulation results show that the proposed algorithm is superior to the iterative constrained weighted least squares algorithm in positioning accuracy in high-noise environment.