The international trend in soil nailed wall design had been evolved from the allowable stress design to limit state design and it is still currently ongoing. The design guidelines in Korea and Hong Kong, still adopts the allowable stress design philosophy while those in others mostly do the limit state design. In this study, four soil nail design methods presented in the major design guidelines(U.S. FHWA GEC 7(2015), Clouterre in France(1991), Soil nailing - best practice guidance in U.K.(CIRIA, 2005), Geoguide 7 in Hong Kong(2008) and Design standard for slope reinforcement work in Korea(KDS 11 70 15 : 2016) are described and analyzed. The factor of safety and CDR(Capacity-to-Demand Ratio) which is used to measure the degree of conservatism of a design guide are obtained for the three cases. One is the design example presented in CIRIA(2005), second is in?situ loading test performed on the top of backfill of the soil nail wall and the other is reinforcement slope’s case of collapsed slope to investigate the conservatism of design guidelines. It is revealed that the design method in overall stability of soil nail walls in Korean design standard(CDR=0.78) is the most conservative and those by Clouterre(CDR=0.99, 1.09), Geoguide 7(CDR=1.13, 0.97), U.S. FHWA(CDR=1.09, 1.07) and CIRIA(CDR=1.40, 1.16) in order from the second most conservative to the least conservative for the design example presented in CIRIA. For the in?situ loading test performed on the top of backfill of the soil nail wall, the order of conservatism are identical except that the places of Geoguide 7(CDR=0.66, 0.72) and FHWA(CDR=0.73, 0.72) are changed. In this study, the Korean design standard of slope reinforcement work(KDS 11 70 15 : 2016) showed the most conservative results in all analysis cases. Then the design standards of FHWA (2015) in the United States, Clouterre (1991) in France, and Geoguide 7 (2008) in Hong Kong showed similar results. The British CIRIA design standard showed the highest CDR(Capacity-to-Demand Ratio) values in all analysis cases. Therefore, the CIRIA design standard was identified as the design method that uses material strength most effectively. Also, this study found out that efforts to improve Korean design standard are needed.