The orientations of focal planes at foci of 30 major deep moonquake groups are surveyed quantitatively based on degree of the coincidence between event occurrence times and peak times of tidal tangential stress variation on hypothetical fault plane. It has been shown that the focal processes of deep moonquake groups are classified to the 'tide-driving type' and 'tide-triggering type'. The former type is defined as nature of deep moonquakes whose fault plane may exist where tidal tangential stress becomes maximum at event occurrence time. It is suggested that the tidal stress is the driving force for this type. The latter type is defined, on the contrary, as nature no plane is there on which tidal tangential stress becomes maximum at that time even though may happen to be fault plane on which the stress becomes minimum. It is suggested that the non-tidal stress plays some driving role for this type. It has been revealed that 19 deep moonquake groups belong to the tide-driving type and 11 groups belong to the tide-triggering type.