Abstract: This paper presents the analytical solutions for describing the initial and subsequent buckling of pipe string in crooked hole. The analytical solutions for the sinusoidal and spiral buckling configurations are obtained from the equilibrium equation, which is based on the equilibrium method. The results are highly consistent with the actual data, and the critical load for initial buckling and spiral buckling, the maximum load for maintaining sinusoidal buckling is further determined. The connection between load and deforming force in the process of subsequent buckling is also disclosed.