A method for transmission mode conversion, wherein the method comprises: detecting, by a terminal, whether a first transmission mode for sending data can be used, wherein the first transmission mode refers to that the terminal sends the data through a first communications resource allocated by a base station; detecting, by the terminal, whether the terminal is within network coverage of the base station, when detecting that the first transmission mode cannot be used; if the terminal is not within the network coverage of the base station: acquiring, by the terminal, an inherent third communications resource, using, by the terminal, a second transmission mode to send the data through the third communications resource, wherein the inherent third communications resource is preconfigured and stored in a storage device of the terminal; if the terminal is within the network coverage of the base station: stopping using, by the terminal, the first transmission mode to send the data and using a second transmission mode to send the data after a first preset time configured to the terminal by the base station, when detecting that the first transmission mode cannot be used, wherein the first preset time balances a number of terminals which are converted to the second transmission mode, and wherein the second transmission mode refers to that the terminal sends the data through a second communications resource selected in a resource pool configured by the base station; and stopping using, by the terminal, the second transmission mode to send the data, and using the first transmission mode to send the data, when detecting that the first transmission mode can be used while the terminal uses the second transmission mode to send the data. detecting, by a terminal, whether a first transmission mode for sending data can be used, wherein the first transmission mode refers to that the terminal sends the data through a first communications resource allocated by a base station; detecting, by the terminal, whether the terminal is within network coverage of the base station, when detecting that the first transmission mode cannot be used; if the terminal is not within the network coverage of the base station: acquiring, by the terminal, an inherent third communications resource, using, by the terminal, a second transmission mode to send the data through the third communications resource, wherein the inherent third communications resource is preconfigured and stored in a storage device of the terminal; if the terminal is within the network coverage of the base station: stopping using, by the terminal, the first transmission mode to send the data and using a second transmission mode to send the data after a first preset time configured to the terminal by the base station, when detecting that the first transmission mode cannot be used, wherein the first preset time balances a number of terminals which are converted to the second transmission mode, and wherein the second transmission mode refers to that the terminal sends the data through a second communications resource selected in a resource pool configured by the base station; and stopping using, by the terminal, the second transmission mode to send the data, and using the first transmission mode to send the data, when detecting that the first transmission mode can be used while the terminal uses the second transmission mode to send the data. acquiring, by the terminal, an inherent third communications resource, using, by the terminal, a second transmission mode to send the data through the third communications resource, wherein the inherent third communications resource is preconfigured and stored in a storage device of the terminal; if the terminal is within the network coverage of the base station: stopping using, by the terminal, the first transmission mode to send the data and using a second transmission mode to send the data after a first preset time configured to the terminal by the base station, when detecting that the first transmission mode cannot be used, wherein the first preset time balances a number of terminals which are converted to the second transmission mode, and wherein the second transmission mode refers to that the terminal sends the data through a second communications resource selected in a resource pool configured by the base station; and stopping using, by the terminal, the second transmission mode to send the data, and using the first transmission mode to send the data, when detecting that the first transmission mode can be used while the terminal uses the second transmission mode to send the data. stopping using, by the terminal, the first transmission mode to send the data and using a second transmission mode to send the data after a first preset time configured to the terminal by the base station, when detecting that the first transmission mode cannot be used, wherein the first preset time balances a number of terminals which are converted to the second transmission mode, and wherein the second transmission mode refers to that the terminal sends the data through a second communications resource selected in a resource pool configured by the base station; and stopping using, by the terminal, the second transmission mode to send the data, and using the first transmission mode to send the data, when detecting that the first transmission mode can be used while the terminal uses the second transmission mode to send the data.