A tubeless fluid delivery device comprising: a controller, comprising a first housing which has a first built-in circuit, wherein the first housing is provided with a first engagement part and a first insertion part electrically connected to the first built-in circuit; and a pump base combined with the controller, which comprises a second housing having a second built-in circuit, a reservoir, a piston, a push rod, a driving member and a battery, wherein the second housing is provided with a second engagement part correspondingly engaged with the first engagement part and a second insertion part electrically connected to the second built-in circuit, wherein the second insertion part is correspondingly inserted in the first insertion part to realize electrical connection between the first built-in circuit and the second built-in circuit; characterized in that the second engagement part is connected to a clamping hook handle, a gap is formed between an inner side of the clamping hook handle and a bottom shell of the pump base, wherein when the clamping hook handle is pressed, the clamping hook handle pushes the second engagement part and disengages it from the first engagement part; in that the first insertion part is a sealed socket, the sealed socket is provided with a groove in which a connector configured to be electrically connected to the first built-in circuit is disposed, wherein an O-shaped sealing ring is set on a surface on which the connector is attached with the sealed socket; and in that the second insertion part is a plug which comprises a plug body circumferentially set with an O-shaped sealing ring and a bolt embedded in the plug body; wherein the bolt is a wedge structure; and wherein when the plug is inserted into the sealed socket, the bolt is inserted into the connector and is electrically connected to the connector, wherein the O-shaped sealing ring on the plug body and the sealed socket fit tightly to achieve water proof sealing. a controller, comprising a first housing which has a first built-in circuit, wherein the first housing is provided with a first engagement part and a first insertion part electrically connected to the first built-in circuit; and a pump base combined with the controller, which comprises a second housing having a second built-in circuit, a reservoir, a piston, a push rod, a driving member and a battery, wherein the second housing is provided with a second engagement part correspondingly engaged with the first engagement part and a second insertion part electrically connected to the second built-in circuit, wherein the second insertion part is correspondingly inserted in the first insertion part to realize electrical connection between the first built-in circuit and the second built-in circuit; characterized in that the second engagement part is connected to a clamping hook handle, a gap is formed between an inner side of the clamping hook handle and a bottom shell of the pump base, wherein when the clamping hook handle is pressed, the clamping hook handle pushes the second engagement part and disengages it from the first engagement part; in that the first insertion part is a sealed socket, the sealed socket is provided with a groove in which a connector configured to be electrically connected to the first built-in circuit is disposed, wherein an O-shaped sealing ring is set on a surface on which the connector is attached with the sealed socket; and in that the second insertion part is a plug which comprises a plug body circumferentially set with an O-shaped sealing ring and a bolt embedded in the plug body; wherein the bolt is a wedge structure; and wherein when the plug is inserted into the sealed socket, the bolt is inserted into the connector and is electrically connected to the connector, wherein the O-shaped sealing ring on the plug body and the sealed socket fit tightly to achieve water proof sealing.