We report experimental results of electrical resistivity, de Haas-van Alphen effect, specific heat and thermal expansion of UPd2Al3. The nominal composition is denoted by the formula of UPd2+xAl3+y. Samples with the composition of UPd2Al3.03 and UPd2.02Al3.03 reveal de Haas-van Alphen oscillations of the magnetic susceptibility. An anomaly is observed in the superconducting phase in the temperature dependence of the specific heat and thermal expansion of UPd2Al3.03. The relation between the sample quality and the appearance of the anomaly is discussed.