Objective To study the influence of crosstalk phenomenon on the measurement of gross radioactivity in drinking water.Methods The gross activity in different standard materials with different thickness and area was measured using national standard method.Results There was no obvious change in crosstalk factor with the increase of 241Am powder amount in the measurement,whereas the larger amount of uranium used might lead to larger crosstalk factor.The different measurement channels resulted in different crosstalk factors.The influence of beta radioactivity on alpha radioactivity measurement was significant.On the contrary,the alpha-to-beta crosstalk factor was negligible.The area of sample plate imposed no significant influence on crosstalk factor.Conclusions The gross beta activity can be corrected to decrease the influence of alpha radioactivity using powder standard samples,when simultaneous alpha and beta counting mode is applied in measurement grass radioactivity in drinking water.