Abstract: The primary mirror deployment mechanism is one of the key parts of the deployable segmented imaging system which is utilized to realize large-aperture and ultra-high resolution for a space optical remote sensor.The basic classification of the primary mirror deployment mechanisms for space optical remote sensors was carried out.The structures,principles and characteristics of(different) primary mirror deployment mechanisms were analyzed.The development trends on(structures),actuators,deploying/locking devices and theoretical studies of future primary mirror(deployment) mechanisms were predicted.Key techniquesand the solutions for primary mirror(deployment) mechanisms were put forward.