An apparatus for executing a computer game is provided. The apparatus includes an output unit configured to transmit a first image generated based on a form of a first user participating in the computer game and a second image generated based on a form of a second user participating in the computer game to a display apparatus, and a control unit configured to predict a possibility of a collision between the first user and the second user, and to control transmitting warning information indicating the possibility of the collision to the display apparatus via the output unit, according to a result of the predicting.