The invention relates to a photovoltaic cell -DC/DC boost conversion charge method which belongs to battery technique field. The method includes: 1) a portable equipment accumulator voltage is detected by a voltage sensor, when lows to full charge capacity, the voltage sensor makes DC/DC boost converter starting DC/DC conversion, and electricity quantity flows from photovoltaic current to lithium battery for charging; 2) when the portable equipment accumulator is in full charge capacity state, accumulator need not charge again, the voltage sensor makes DC/DC boost converter forbidding DC/DC conversion, thereby, the portable equipment accumulator is protected and over charge phenomena is prevented. The method can be realized simply, and has short reaction time, high efficiency, overvoltage protection and anti-counterblast protection.