Accurate de novo protein structure prediction remains a fundamental challenge, particularly in cases where homologous templates are unavailable or evolutionary information is weak. While end-to-end methods such as AlphaFold2 have achieved unprecedented accuracy, their closed box nature provides limited insight into the folding process and offers little flexibility for incorporating external evaluation. Here, we investigate whether model quality assessment (MQA) can be integrated into the structure prediction pipeline as a closed-loop feedback mechanism to iteratively improve prediction accuracy. In this study, we propose DGMFold, a de novo protein structure prediction method that establishes a feedback loop among three components: the geometric constraint prediction network (GeomNet), the structural simulation module, and the model quality evaluation network (EmaNet). In GeomNet, co-evolutionary features extracted from multiple sequence alignments (MSAs) are fed into an improved residual neural network to predict inter-residue geometric constraints, which are then used to guide structure folding. EmaNet then extracts 1D and 2D features from the folded structure model and employs a deep residual neural network to estimate the inter-residue distance deviation and per-residue lDDT. These evaluations are subsequently fed back into GeomNet as dynamic features, enabling iterative refinement of the predicted geometries and overall model accuracy. DGMFold was tested on 437 benchmark proteins and 20 FM targets of CASP14. Experimental results demonstrate that the closed-loop feedback mechanism significantly contributes to the performance of DGMFold, and the prediction accuracy of DGMFold outperforms that of the state-of-the-art de novo methods trRosetta and RaptorX at the time. When evaluated on the 124 human proteins for which AlphaFold2 yields TM-scores below 0.9, DGMFold achieves higher prediction accuracy than AlphaFold2 and RoseTTAFold on 71 and 72 targets, respectively, and outperforms both on 58 proteins.