Based on the Contrastive Analysis Hypothesis suggested by Lado and others, the English and Cantonese consonants were analysed and compared. Attempts were made to predict the pronunciation errors Cantonese speakers would make in the process of learning English. Seven Cantonese speaking immigrants from Hong Kong who had been in Canada ranging from three months to eight months were chosen to read the Diagnostic Passage of the Manual of American English Pronunciation written by Prator and Robinett (1972). Their readings were transcribed and analysed. Allophonic errors made by the subjects were also considered. The results showed that most of the pronunciation errors that made by the subjects were those that were predicted. Finally, a hierarchy of difficulty of the English consonants was set up to serve as a guideline for those who teach English to Cantonese students, and for those who are engaged in the preparation of testing materials for Cantonese speakers of ESL.