The helical-effect of helical and twisted reinforcement material is analyzed. Through analyzing the geometrical parameters of the helical and twisted material,a mechanism model based on the bond of anchorage is established.Furthermore the fundamental derivation formula is proposed and the sensitivity is analyzed.The result proves that the pitch of the helical and twisted material affects the first peak little,but has remarkable effect on the second peak of the curve of the load-slip.These theoretical results match the result of pullout test on the helical and twisted steel and fiber.The universality of helical-effect is proved theoretically.