The deactivation of the supported bimetallic Pd-Pb catalyst in the repeated runs of direct oxidative esterification of methacrolein with methanol in the atmosphere was investigated. The catalysts before and after stability tests were characterized by X-ray diffraction, transmission electron microscopy, X-ray photo-electron spectroscopy, inductively coupled plasma mass spectrometry, Brunauer-Emmett-Teller method and thermogravimetric analysis. The results indicated that the major factor affecting the deactivation of the catalyst was the deposition of organic substances on the surface active sites of the catalyst during batch reaction. Washing the deactivated catalyst with either MeOH or an aqueous hydrazine solution at 80 degrees C could completely recover the initial activity of the catalyst, and calcining the deactivated catalyst in air at 500 degrees C and then reducing in an aqueous hydrazine solution could partly recover its activity. The deactivation and regeneration of the catalyst in the direct oxidative esterification at gas-liquid-solid phase are important and meaningful. (c) 2013 Elsevier B.V. All rights reserved.