The invention provides a telescopic type suspension arm splitting method, which comprises a step S1 of extending out a to-be-dismantled suspension arm (40), then extending out a to-be-reserved suspension arm (30) connected with the to-be-dismantled suspension arm (40), and exposing a suspension arm pin (50) which is connected with the to-be-dismantled suspension arm (40) and the to-be-reserved suspension arm (30); a step S2 of carrying out amplitude variation to a telescopic type suspension arm, enabling the telescopic type suspension arm to be inclined downwards along the extending-out direction, and fixing the telescopic type suspension arm; a step S3 of retracting the suspension arm pin (50), and dismantling the to-be-dismantled suspension arm (40) from the inside of the to-be-reservedsuspension arm (30). The telescopic type suspension arm splitting method can reduce splitting difficulty of the telescopic type suspension arm, reduces labor intensity, improves working efficiency, and prolongs service life of the suspension arm pin.