Payne, unbeaten on 48 when bad light ended play, joined Dent (86) at the crease with his side struggling at 97-7, before helping them to 201-7.
Gloucestershire lost three wickets in the morning, when they scored only 33 runs from 24 overs, with 129 dot balls.
Paceman Steve Magoffin led the way for Sussex, taking 3-35 from his 19 overs.
Chris Dent and David Payne provided timely resistance for Gloucestershire against a suffocating Sussex bowling performance on the opening day.