A method for accessing a network by using a virtual SIM card, comprising: determining, by a mobile device, from a pre-stored primary virtual SIM card packet sent by a virtual SIM card server, at least two candidate primary virtual SIM cards that match a network environment parameter of a visited place of the mobile device, wherein a service coverage area of the primary virtual SIM card packet comprises the visited place; and wherein the primary virtual SIM card packet comprises a plurality of primary virtual SIM cards from each of a plurality of providers; wherein the network environment parameter comprises a network number of a mobile network found in the visited place, and the determining, by the mobile device from the pre-stored primary virtual SIM card packet, at least two candidate primary virtual SIM cards that match the network environment parameter includes: querying, by the mobile device, a set of network numbers, each network number representing a network supported by primary virtual SIM cards in the primary virtual SIM card packet; and determining at least two sets of network numbers comprising the network number and at least two candidate primary virtual SIM cards corresponding to the at least two sets of network numbers; downloading, by the mobile device, a secondary virtual SIM card by using an accessed primary virtual SIM card that is in the at least two candidate primary virtual SIM cards and that successfully registers with and accesses a network; wherein the primary virtual SIM card packet further comprises provider quality weights of the networks supported by the primary virtual SIM cards, and the downloading a secondary virtual SIM card by using an accessed primary virtual SIM card that is in the at least two candidate primary virtual SIM cards and that successfully registers with and accesses a network comprises: registering with and accessing the network in ascending order of the provider quality weights by using the at least two candidate primary virtual SIM cards, determining an accessed primary virtual SIM card that can successfully register with and access the network, and downloading the secondary virtual SIM card by using the accessed primary virtual SIM card to access the network; and accessing, by the mobile device, a target mobile network of the visited place by using the secondary virtual SIM card. determining, by a mobile device, from a pre-stored primary virtual SIM card packet sent by a virtual SIM card server, at least two candidate primary virtual SIM cards that match a network environment parameter of a visited place of the mobile device, wherein a service coverage area of the primary virtual SIM card packet comprises the visited place; and wherein the primary virtual SIM card packet comprises a plurality of primary virtual SIM cards from each of a plurality of providers; wherein the network environment parameter comprises a network number of a mobile network found in the visited place, and the determining, by the mobile device from the pre-stored primary virtual SIM card packet, at least two candidate primary virtual SIM cards that match the network environment parameter includes: querying, by the mobile device, a set of network numbers, each network number representing a network supported by primary virtual SIM cards in the primary virtual SIM card packet; and determining at least two sets of network numbers comprising the network number and at least two candidate primary virtual SIM cards corresponding to the at least two sets of network numbers; querying, by the mobile device, a set of network numbers, each network number representing a network supported by primary virtual SIM cards in the primary virtual SIM card packet; and determining at least two sets of network numbers comprising the network number and at least two candidate primary virtual SIM cards corresponding to the at least two sets of network numbers; downloading, by the mobile device, a secondary virtual SIM card by using an accessed primary virtual SIM card that is in the at least two candidate primary virtual SIM cards and that successfully registers with and accesses a network; wherein the primary virtual SIM card packet further comprises provider quality weights of the networks supported by the primary virtual SIM cards, and the downloading a secondary virtual SIM card by using an accessed primary virtual SIM card that is in the at least two candidate primary virtual SIM cards and that successfully registers with and accesses a network comprises: registering with and accessing the network in ascending order of the provider quality weights by using the at least two candidate primary virtual SIM cards, determining an accessed primary virtual SIM card that can successfully register with and access the network, and downloading the secondary virtual SIM card by using the accessed primary virtual SIM card to access the network; and accessing, by the mobile device, a target mobile network of the visited place by using the secondary virtual SIM card.