Based on the monthly samples caught by bottom trawls in the Beibu Gulf of the South China Sea from November 2008 to September 2009,the biological information and stomach contents were collected for analysis of feeding habits.The stable isotope analysis was also used to study the prey category,trophic level and ontogenetic feeding habits of P.edita.The results showed that P.edita preyed widely in the Beibu Gulf,including twenty-three species such as small pelagic and bottom fishes,benthic crustacean,cephalopoda and so on.Among them,fishes account for 79.74%.The dominant fish prey was Bregmaceros macclellandii which appeared every month,comprising 58.38% of total food weight.Crustacean and cephalopoda account for 10.86% and 6.97%.The trophic shift was found in P.edita according to the index of relative importance(IRI%).Those P.edita whose standard length ranged from 30 mm to 59 mm mainly feed on small zooplankton,while those with standard length greater than or equal to 60 mm mainly feed on large forage fish and benthic invertebrates(shrimps,crabs,and cephalopodas).The average repletion index significantly changed with the standard length(P<0.05),so did the gonad maturity index(P<0.05).The vacuity coefficient also significantly changed with the standard length(P<0.05),but there was no significant difference in gonad maturity alteration.The nitrogen stable isotope ratios were from 12.009×10^-3 to 16.007×10^-3.The trophic levels of P.edita calculated from δ¹⁵N did not differ notably with the standard length and month shift.The average trophic level was calculated by prey weight percentage and δ¹⁵N and it was 3.1 and 3.7,respectively.