The change of hit record set affects re call ratio and pertinency ratio greatly in the computer information retrieval.In this paper,the regularity of hit record set in the computer information retriev al is studied in theory and in practice.It’s found both in the specific retriev al examples that the hit record set may remain unchanged,decrease,increase or be the combination of them with the increase or decrease of the retrieval facets in queries.It provides an essential basis for the research on the relations betwee n recall ratio and pertinency ratio.
