An on-chip optical trapping and sorting system composed of a microchamber and a microlens array (MLA) is demonstrated. The MLA focuses the incident light into multiple confocal spots to trap the particles within the microchamber. The ${\mathrm{SiO}}_2/{\mathrm{ZrO}}_2$ solgel material is introduced in the fabrication of MLA for its unique optical and chemical characters. Moreover, in order to prove the effectiveness of the system, experimental demonstration of multibeam trapping and locked-in transport of micropolymer particles in the microchamber is implemented. The system may easily be integrated as microfluidic devices, offering a simple and efficient solution for optical trapping and sorting of biological particles in lab-on-a-chip technologies.