The present study demonstrates an intensive experimental work based on the tin oxide (SnO2) nanoparticle synthesis which was successfully carried out by a simple conventional precipitation method followed by calcination at 700 °C. The synthesized nanoparticles were characterized by X-ray powder diffraction (XRD), UV-Vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM) and energy-dispersive X-ray spectroscopy (EDAX). The XRD pattern proves that tetragonal rutile structure SnO2 nanoparticles were formed. The crystallite particle size calculation from Scherer's equation revealed the average size of 28.5 nm. The absorption spectrum of SnO2 nanoparticles showed absorption band at about 290 nm and the band gap energy (Eg) from Tauc plot was obtained at 3.8 eV. The photocatalytic degradation of pharmaceutical compound, 4-aminopyridine (5 ppm) using synthesized SnO2 nanoparticle, was assessed. The effect of variable catalyst dosage, pH and irradiation sources, were studied. The optimum catalyst dosage and pH were found to be 1.5 gm/L and 6.5, respectively. The degradation efficiency of water contaminant 4-aminopyridine under UV light and solar light irradiation for 120 min were found to be 97% and 11%, respectively. The reusability of the catalyst was checked and has been found stable after three photocatalytic runs.