An SIM card implementation method with a built-in digital wallet function comprises the following steps that an SIM card receives an instruction of an intelligent terminal to start a digital currencysystem; Receiving a PIN code input by a user, and starting a digital currency account; Confirming a digital currency transaction type; Confirming a digital currency transaction mode with the intelligent terminal; And performing a digital currency transaction and finishing the transaction. The invention further provides the SIM card with the built-in digital wallet function, the digital wallet function is integrated into the SIM card on the premise that safety is guaranteed, and therefore digital currency transaction can be conducted anytime and anywhere without additionally carrying a digitalwallet.