Agricultural zoning is a major mean of farmland conservation and it has been a key component in policy for the prevention of urban sprawl and nonagricultural development of farmland in Taiwan. However, despite political commitments to the policy, there is currently little empirical evidence regarding the actual economic impact and effectiveness of this policy. This study adds to current knowledge by assessing the effect of agricultural zoning policy based on the Regional Planning Act which was amended in 2000 in Taiwan and using big data in combination with datasets from a management information system (MIS) and geographic information system (GIS). With the assistance of the GIS, we extracted geospatial and analytic data from map profiles along with data from a social economic dataset. By using the repeated cross-sectional zoning data at a village level and information about paddy planting areas for the first crop season in 2010 and in 2014, we applied a random effects panel regression to examine the influences of the planned zoning on cropland. Our results demonstrate that the zoning impact on paddy fields located in common agricultural zones is a significant decrease in area of about 4 hectares. However, within special agricultural districts and urban planning areas, the zoning effects seem to be positive but insignificant. This suggests the agricultural zoning policy in Taiwan is likely to discourage farmers from faming, which may prompt them to engage in alternative land use.