Photoacoustic (PA) imaging is a modality for achieving high-contrast images of blood vessels or tumors. Most PA imaging systems use complex reconstruction algorithms under conventional linear array transducers. We introduced the optical simulating method to improve the acoustic lens design and obtain a PA imaging system with improved spatial revolution (a 0.5-mm point spread function and a lateral image resolution of more than 1 mm) is realized using a 4f aspherical acoustic lens. The acoustic lens approach improved the image resolution and enabled direct reconstruction of three-dimensional (3-D) PA images. The system demonstrated a lateral resolution of more than 1 mm, a field of view of 8.5 deg, and a depth of focus of 10 mm. The system displays great potential for developing a real-time 3-D PA camera system for biomedical ultrasound imaging applications.