A series of Pb(Ti1-xAlx)O-3, Pb(Ti1-xNbx)O-3 and Pb(Ti1-xAlx/2Nbx/2)O-3 thin films were fabricated onto Pt/Ti/SiO2/Si(100) substrates using a chemical solution deposition process. The dielectric constant of the Pb(Ti1-xAlx)O-3 thin films increased with increase of aluminum content, while a maximum dielectric constant value was observed for the Pb(Ti1-xNbx)O-3 and Pb(Ti1-xAlx/2Nbx/2)O-3 thin films when the doping contents were 10 and 20 mol%, respectively. The dielectric constant of the Pb(Ti0.8Al0.1Nb0.1)O-3 thin film is about 600, being two times higher than those of Pb(Ti0.9Al0.1)O-3 and Pb(Ti0.9Nb0.1)O-3 thin films. The Pb(Ti0.8Al0.1Nb0.1)O-3 thin film showed less than 10(-7) A/cm(2) current density at +/- 150 kV/cm, being superior to the leakage property of the PbTiO3, Pb(Ti0.9Al0.1)O-3 and Pb(Ti0.9Nb0.1)O-3 thin films. The co-doping of aluminum and mobium is more effective to increase the dielectric and ferroelectric properties as compared with the individual aluminum or niobium doping.