mouse intestinal stem cells and primary colorectal cancer cells can be propagated in vitro long term, [1] there is an urgent need to develop more physiologically relevant, efficient, and robust precise oncology models that closely recapitulate the genetic and morphological heterogeneous composition and mimic the arrangement pattern of cancer cells in the original tumor. [2] To our knowledge in biomedical research, hydrogel is the best tool to reconstruct precise oncology models in vitro, especially tumor organoid, which not only recapitulates in vivo biology and microenvironmental factors, but also at large extent allows side-by-side comparison to evaluate the translational potential of 3D model systems to the patients. [2a,3] Generally, hydrogels are mainly composed of hydrophilic polymeric scaffolds that absorb large amounts of water, so the hydrogel matrix better mimics elastic and viscoelastic properties in ECM and microscale topographies of cell matrices, which controls proper cell morphology, directs viable cell behaviors, and drives in vivo fundamental cell-cell or cell-ECM interactions. [4] To recapitulate pathophysiological features of human tumors and imitate various aspects of human tumorigenesis in vivo, hydrogels can provide a realistic platform to establish a useful bridge between in vitro assays and in vivo cell microenvironments. In current biomedical applications, there are many kinds of hydrogels to be developed to mimic the biological properties of ECM, such Designer self-assembling peptides form the entangled nanofiber networks in hydrogels by ionic-complementary self-assembly. This type of hydrogel has realistic biological and physiochemical properties to serve as biomimetic extracellular matrix (ECM) for biomedical applications. The advantages and benefits are distinct from natural hydrogels and other synthetic or semisynthetic hydrogels. Designer peptides provide diverse alternatives of main building blocks to form various functional nanostructures. The entangled nanofiber networks permit essential compositional complexity and heterogeneity of engineering cell microenvironments in comparison with other hydrogels, which may reconstruct the tumor microenvironments (TMEs) in 3D cell cultures and tissue-specific modeling in vitro. Either ovarian cancer progression or recurrence and relapse are involved in the multifaceted TMEs in addition to mesothelial cells, fibroblasts, endothelial cells, pericytes, immune cells, adipocytes, and the ECM. Based on the progress in common hydrogel products, this work focuses on the diverse designer self-assembling peptide hydrogels for instructive cell constructs in tissue-specific modeling and the precise oncology remodeling for ovarian cancer, which are issued by several research aspects in a 3D context. The advantages and significance of designer peptide hydrogels are discussed, and some common approaches and coming challenges are also addressed in current complex tumor diseases.