  We investigate relations among tree-level off-shell currents in nonlinear
sigma model. Under Cayley parametrization, we propose and prove a general
revised BCJ relation for even-point currents. Unlike the on-shell BCJ relation,
the off-shell one behaves quite differently from Yang-Mills theory although the
algebraic structure is the same. After performing the permutation summation in
the revised BCJ relation, the sum is non-vanishing, instead, it equals to the
sum of sub-current products with the BCJ coefficients under a specific
ordering, which is presented by an explicit formula. Taking on-shell limit,
this identity is reduced to the on-shell BCJ relation, and thus provides the
full off-shell correspondence of tree-level BCJ relation in nonlinear sigma
model.
