The invention relates to a method for external connection of a storage card for a mobile phone, which is achieved through the following modes: (1) connecting four GPIO interfaces of the mobile phone with DO, SC, CLK and DI signal wires of an external storage card respectively; (2) setting the first GPIO interface connected with the DO signal wire in an input mode, and setting the second, the thirdand the fourth interfaces connected with the CS signal wire of the external storage card respectively in an output mode by using a control register storing an SPI interface function in the mobile phone; and (3) when the mobile phone is electrified and reset, if the external storage card is detected to be connected with the mobile phone, setting the signals of the second GPIO interface to have a low level. The method uses the control register storing the SPI interface function in the mobile phone to control the prior frequently used GPIO interfaces of the mobile phone so as to achieve the datacommunication with the external storage card without additional hardware cost, the circuit structure is simple and easy to achieve, and a low-middle end mobile phone can achieve the function of having the external storage card.