The invention discloses an arc-shaped slide core-pulling mechanism for a plastic mould. The arc-shaped slide core-pulling mechanism comprises a front mould and a rear mould. An insert is arranged between the front mould and the rear mould. The arc-shaped slide core-pulling mechanism is characterized in that an arc-shaped slide casting insert capable of rotating is arranged in the insert, and connected to the front mould through a rotating shaft, a first slide mechanism is arranged on the rear mould, product positions are formed among the first slide mechanism, the outer wall of the arc-shaped slide casting insert and the outer wall of the rear mould, the first slide mechanism comprises a first slide arranged in a receding groove of the rear mould, a shovel base enabling the first slide to abut against the arc-shaped slide casting insert is arranged on the rear mould, and a drive mechanism capable of driving the shovel base to retreat and driving the arc-shaped slide casting insert to rotate to demould is arranged between the front mould and the rear mould. The arc-shaped slide core-pulling mechanism for the plastic mould is simple in structure and convenient to install, enables the slide with the R-angle plastic position to be released forcibly and then demoulded, and effectively reduces product strain.