A method and apparatus for allocating and processing sequences in a communication system is disclosed. The method includes: dividing sequences in a sequence group into multiple sub-groups, each sub-group corresponding to its own mode of occupying time frequency resources; selecting sequences from a candidate sequence collection corresponding to each sub-group to form the sequences in the sub-group by: the sequences in a sub-group i in a sequence group k being composed of n sequences in the candidate sequence collection, the n sequences making a |ri/Ni−ck/Np1| or |(ri/Ni−ck/Np1) modu mk,i| function value the smallest, second smallest, till the nth smallest respectively; allocating the sequence group to cells, users or channels. It prevents the sequences highly correlated with the sequences of a specific length from appearing in other sequence groups, thus reducing interference, avoiding the trouble of storing the lists of massive sequence groups.