A method for establishing a connection between a mobile terminal and a WiFi network, comprising: determining (S101, S201, S301, S401) a security level of the current WiFi network; marking (S102, S202, S302, S402) a WiFi signal icon according to a color corresponding to the security level; and showing (S103, S203, S303, S403) the marked WiFi signal icon, characterized in that the security level is set by a user according to requirements, the method further comprises: monitoring (S204, S304, S404) whether there is a WiFi network having a security level higher than the current WiFi network; and when there is the WiFi network having the security level higher than the current WiFi network, controlling (S205, S306) the mobile terminal to connect to the WiFi network having the highest security level currently, and when it is monitored that there are a plurality of WiFi networks having security levels higher than the current WiFi network, the method further comprises: ranking the WiFi networks having the security levels higher than the current WiFi network in an order of the security levels from high to low; and controlling the mobile terminal to connect to a target WiFi network according to a user selection instruction, the user selection instruction carrying an identity of the target WiFi network. determining (S101, S201, S301, S401) a security level of the current WiFi network; marking (S102, S202, S302, S402) a WiFi signal icon according to a color corresponding to the security level; and showing (S103, S203, S303, S403) the marked WiFi signal icon, characterized in that the security level is set by a user according to requirements, the method further comprises: monitoring (S204, S304, S404) whether there is a WiFi network having a security level higher than the current WiFi network; and when there is the WiFi network having the security level higher than the current WiFi network, controlling (S205, S306) the mobile terminal to connect to the WiFi network having the highest security level currently, and monitoring (S204, S304, S404) whether there is a WiFi network having a security level higher than the current WiFi network; and when there is the WiFi network having the security level higher than the current WiFi network, controlling (S205, S306) the mobile terminal to connect to the WiFi network having the highest security level currently, and when it is monitored that there are a plurality of WiFi networks having security levels higher than the current WiFi network, the method further comprises: ranking the WiFi networks having the security levels higher than the current WiFi network in an order of the security levels from high to low; and controlling the mobile terminal to connect to a target WiFi network according to a user selection instruction, the user selection instruction carrying an identity of the target WiFi network. ranking the WiFi networks having the security levels higher than the current WiFi network in an order of the security levels from high to low; and controlling the mobile terminal to connect to a target WiFi network according to a user selection instruction, the user selection instruction carrying an identity of the target WiFi network.