Tubular hydrogel scaffolds facilitate nutrient and oxygen transport, making them particularly suitable for culturing cells with high metabolic demands. In this study, a double-network hydrogel scaffold with a tubular structure was fabricated using coaxial extrusion-based 3D printing. The hydrogel was composed of sodium alginate and polyacrylamide, and its biocompatibility was assessed through cell culture experiments. The results show that the crosslinking sequence, material composition, and printing parameters were the main factors affecting the macrostructure, microstructure, and mechanical properties of the hydrogel. The CA-PAm hydrogel, in which alginate was ionically crosslinked before subsequent acrylamide (AAm) polymerization under UV exposure, exhibited a more compact microstructure and superior mechanical performance. By optimizing the material composition, the CA-PAm hydrogel achieved a tensile strength of 809.80 kPa and an elongation at break of 217.07%. In addition, the inner-to-outer flow-rate ratio and the platform moving speed are critical factors determining the tubular structural parameters and 3D structural stability. The hydrogel leachate assay showed 89.8% cell viability, and perfusion culture within the tubular scaffold showed an MEF survival rate of 85.4% after three days, indicating good biocompatibility of the scaffold. These results show that crosslinking-sequence reconfiguration is a practical strategy for matching hydrogel network formation with the requirements of coaxial tubular printing and provides a feasible route for fabricating mechanically robust and cytocompatible hollow hydrogel scaffolds for tissue engineering.