A method is proposed to prepare a liquid crystal lenticular lens array (LCLA) with switchable positive and negative focal length. The LCLA exhibits a “sandwich” structure which consists of top electrode substrate, LC layer, polymeric lenticular lens array, and bottom electrode substrate. In order to integrate the convergence and divergence functions in a single LC cell, the refractive index of the polymer should be between the ordinary refractive index (n_o) and exordinary refractive index (n_e) of LC material. The hydrophobic-hydrophilic strips array modified on the surface of the bottom substrate enables the formation of lenticular lens array self-assembly. There are two methods to switch the focal length of LCLA from negative to positive values: by changing the polarization direction of the incident light for 90°; or by applying an external electric field to adjust the effective refractive index of the LC layer. The experimental results show that when the applied voltage adjusted from 0 V_rms to 0.7 V_rms, the focal length of the LCLA changed from -4 mm to ∞. When the applied voltage changed from 1 V_rms to 7 V_rms, the focal length of the LCLA varied from 6.0 mm to 4.5 mm. The as-obtained LCLA has the advantages of simple fabrication, compact structure, low driving voltage and large range of focal length, which has potential applications in the fields of imaging, display, and optical communication.