Bioretention is a typical low-impact development (LID) technology. This work used four different filler combinations of bioretention tank pilot test devices. Experiments on influence factors and intermittent operation were conducted. A continuous-run experiment was also performed to determine the purification ability of bioretention system on heavy metals. Results showed that the removal efficiency of heavy metals by fly ash tank was the most efficient, with a removal rate reaching 85.57%. The removal effect on highinfluent concentrations in filter was better than that in low-influent concentrations. With increased rainfall time intervals (antecedent dry time), heavy-metal removal efficiency improved. Temperature did not affect the removal efficiency of heavy metals on the whole based on the long duration of intermittent operation experiments. Moreover, the effluent heavy-metal concentration presented a descending trend during each simulation rainfall runoff event. During continuous operation test, heavy metals did not reach the exhaustion point in the experimental tanks, while the effluent concentration increased with increased water volume. According to PLS regression analysis, rainfall time interval was the most important factor affecting Zn removal rate, followed by filler characteristics, influent volume, and influent concentration.