The present invention discloses a lead-acid battery charging method, multiple charging modes are set. In the normal mode, according to battery capacity, charge batteries in multi-stages. The corresponding charger is disclosed which comprising of: high-power switch power supply, switch circuit, impulse charge-discharge circuit, voltage and current detecting circuit, charge mode switch module and micro-processor. Comparing to present technique, the present invention sets multiple charge modes, charges in multi-stages, meets the charge requirement in all different conditions furthest, and benefits for prolonging the service life of lead-acid battery. The pulse charge-discharge circuit of present invention realizes discharge energy circumfluence by capacitance serial-parallel conversion, uses high inductance converting steep wave pulse to ladder-type pulse, comparing to traditional pulse charge-discharge circuit using big resistance charge and discharge, reduces the energy loss and loss of rapid pulse to lead-acid battery electrode slices.