A method, a user equipment, and a base station are provided for acquiring and transmitting system information. The method is applicable to the user equipment, and includes: a message of random access is transmitted to a base station, where the message of random access includes first request information for requesting system information; first instruction information transmitted by the base station according to the first request information is received, wherein the first instruction information instructs the user equipment to enter a connected state for receiving the system information; a communication connection is established with the base station; and first radio resource control information transmitted by the base station is received, and the system information is extracted from the first radio resource control information.