Within　the　range　of　pressure　from　23　to　28　MPa,　mass　flux　from　350　to　1000　kg/　(m2·　s),　and　outside　wall　heat　flux　from　200　to　1000　kW/m2,　experimental　investigation　was　conducted　on　the　heat　transfer　characteristics　of　supercritical　pressure　water　in　vertical　upward　annular　channels.　The　effects　of　heat　flux,　pressure,　mass　flux　and　spiral　spacer　on　heat　transfer　were　analyzed,　and　two　types　of　heat　transfer　deterioration　occurred　in　the　experiments　were　compared.　The　experimental　results　show　that　the　heat　transfer　of　water　can　be　enhanced　by　increasing　the　mass　flux　or　decreasing　the　wall　heat　flux.　The　effect　of　pressure　on　heat　transfer　is　not　uniform　and　depends　on　heat　transfer　form.　It　was　found　that　the　spiral　spacer　not　only　enhances　the　heat　transfer　of　water,　but　also　delays　the　heat　transfer　deterioration　which　occurs　in　high　heat　flux　and　low　mass　flux　conditions.