Background: to evaluate the color stability and marginal gap of different types of zirconia crowns with two preparation designs. materials and methods: two upper left centrals typodonts were prepared with two different preparation designs; vertical preparation and horizontal preparation with shoulder finish line0.5mm depth. Each typodont was scanned for designing full coverage crowns and duplication to 3D printed dies (n=21).21 crowns were milled for each preparation design and furtherly divided according to the material into three groups(n=7) as follows; zirconia YZ XT, IPS e-max zircad prime and vita suprinity then each crown is cemented to its corresponding die. Marginal gap analysis for both vertical and horizontal crown samples were measured using stereomicroscope with (300X) power. Color analysis of the crowns was performed by means of Agilent Cary 5000 spectrophotometry before and after 5000 thermal cycles to calculate ΔE, the data were analyzed statistically significant using two-way anova at significance value (p≤0.05). Results: the type of the material(p˂0.001) as well as the preparation type(p=0.004) resulted in significant change in ΔE, zircad crowns with horizontal finish lines showed the highest color stability with ΔE=2.51, regarding the marginal gap analysis the preparation type only showed significance (p˂0.001) with higher gap values to vertical preparations samples. Conclusion: the color stability before and after thermocycling is affected with both the type of material and preparation type, yet the marginal gap only affected by the preparation type with no correlation with color stability.