We construct colliding plane wave solutions in higher dimensional gravity theory with dilaton and higher form flux, which appears naturally in the low energy theory of string theory. Especially, the role of the junction condition in constructing the solutions is emphasized. Our results not only include the previously known CPW solutions, but also provide a wide class of new solutions that is not known in the literature before. We find that late time curvature singularity is always developed for the solutions we obtained in this paper. This supports the generalized version of Tipler's theorem in higher dimensional supergravity. 10 4.2 Physical flux-CPW solution 13 4.3 Future singularity of the solution 14 5. Conclusions and Discussions 16 A. Ricci and Riemann tensors 17 B. On the O'Brien-Synge Junction Conditions and Beyond 18 C. CPW solution without flux 20 D. Boundary behaviour of the CPW solution 21 E. Incoming wave in the Brinkmann coordinates and Impulsive wavefront 23struct the CPW with an electromagnetic (EM) field shock wave profile [14]. In the setting they considered, a EM potential is included. Therefore a P.C. stress tensor is allowed; and so is the same for the Ricci tensor. Bell and Szekeres thus proposed to consider piecewise C 1 metric which admits a P.C. Ricci tensor. Since for a general piecewise C 1 metric, the Ricci tensor contains a δ-function singularity, it is necessary to impose further conditions on the piecewise C 1 metric such that the δ-function singularity does not appear. These are precisely the O'Brien-Synge (OS) junction conditions [15]. See our appendix B for a detailed exposition.Apart from the above-mentioned δ-function singularity, it is also possible that the curvature invariants R and R 2 1 blow up at the junction. This should be avoided for a physical solution and generally requires additional condition besides the Lichnerowicz/O'Brien-Synge junction conditions. Our section 3 contains a general discussion on this point.Most of the discussions of CPW have been limited to the 4-dimensional gravity with or without a EM field. Dilatonic gravitational CPW with a EM field has been considered [16]. Higher dimensional generalization of the Bell-Szekeres solution of Maxwell-Einstein gravity has also been attempted recently [17]. As we will demonstrate in section 4, the later solutions however violate the OS junction conditions and are thus not acceptable. Recently, Gutperle and Pioline [18] has tried to construct the CPW in 10-dimensional IIB string theory with the self-dual form flux; for latter convenience, we call the general CPW with form flux the "flux-CPW". However, they found that the curvature invariants blow up at the junction so that the solutions cannot be used to describe the flux-CPW. The goal of this paper is to construct regularly patched flux-CPW solution in string theory, and we find that the key ingredient is to turn on the dilaton field.