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Dislocation distribution near the crack tip of I and II modes in bulk aluminum single crystal has been decorated by using the etching pit technique and then was observed by scanning electron microscopy. It has been shown that two kinds of distribution of dislocations, i.e., shielding and antishielding dislocations are found to exist near the crack tip. In addition to these, the dislocation-free zone is still observed to be between the crack tip and the plastic zone. According to Rice and Thomson [Philos. Mag. 29, 73 (1974)], the dislocation mode of the elastic-plastic crack is extended to include the antishielding dislocations as part of a crack-tip equilibrium configuration, which may be described as follows: (mu-b/2-pi) (S-a-e + S-s-c + S(c)s + S(e)a) [f(x')/(x - x')]dx' + sigma-a = 0, when /x/ < C, or sigma-f, when c < /x/ < s and e < /x/ < a. The factor affecting the dislocation distribution are discussed in detail.