This text tries to explore the dialectical relation between testimony documentary and artistic concept in the contemporary documentary art, and the political issues leading to contemplation in current society. From the objective document of single image in the traditional photography, the multiple structure of photomontage, the performance of conceptual documentary art, or the pseudo-documentation of discussing the reality, etc., these gradually become diversified forms in the area fo documentary art. On one hand, the characteristic of the contemporary documentary art lies in the diversified use of new photographic concept, which may evolve the sequential, serial, or archival form. On the other hand, these documentaries arts that connected to the objective fact or to the subjective expression of individual artist, whether this can further explain the cultural or political power of contemporary social problem? This text aims to exploring and observing the characteristic of documentary art through some works of documentary image in 52[8e60] Biennale di Venezia. In the diversified and open areas of contemporary art, the emphasis lies no longer in debating the double characteristics between the pure art and the documentary. Instead, the attention turns more to the profound investigation about politics and society or to the criticism and narration of art discipline.